The Southwestern Comprehensive Sickle Cell Center (the "Center"), which has served as one of the ten NHLBI-funded Centers during 2003-2008 grant cycle, is applying for continued support during the next funding cycle. The Center, based at the University of Texas Southwestern Medical Center at Dallas (UT Southwestern) and Children's Medical Center Dallas (CMCD), will continue to include other collaborating medical centers whose physicians and other personnel are dedicated to the care of persons with sickle cell disease and the conduct of novel clinical, translational, and health services research. These other Centers are the University of Texas at Dallas, the University of Oklahoma Health Sciences Center, the University of Texas Medical Branch at Galveston, and the University of Florida College of Medicine. The Center's track record during the current grant period in the CSCC Clinical Trials Consortium has been exemplary. Center investigators lead two of the five national clinical trials opened thus far and play prominent roles on Consortium committees. Moreover, clinical trial enrollment from the multiple sites in our Center has been substantial. The Center currently ranks second overall among the ten comprehensive centers in patient enrollment. The Center is also successfully executing basic science, clinical intra-Center, and a variety of other collaborative and institutional research protocols, accompanied by smoothly functioning administrative and patient services cores. The Center plans to continue and appreciably expand myriad research, patient care, education, and advocacy initiatives during the next five years. A cohesive, interactive, and collaborative spirit exists among Center investigators and their institutions, thus assuring the Southwestern Comprehensive Sickle Cell Center's continued success.